Gestalt switch. Is the dress yellow and gold or blue and black? Is the image a duck or a rabbit? Did the Kremlin murder Boris Nemtsov, or was it the CIA? In the social media age, the death of the Russian opposition leader passed over the conspiracy-theory event-horizon within 24 hours of its taking place. By that I mean — and the comparison with that wretched dress is not intended frivolously — it has arrived in a position where such evidence as we have is capable of standing simultaneously for one thing and for its diametric opposite.

The carnage was much the same as at any club when three o’clock comes around. The hardcore ravers ran around shirtless, covered in fluorescent paint. The lost souls stumbled around, listlessly swigging from bottles. Such was the scene at the Big Fish Little Fish Family Rave at the Festival Hall on Sunday afternoon.